@mercime I defined a child theme and it’s activated, default.css is imported and I changed some margins with it. But… honestly speaking I couldn’t make sub pages’ menu to be opened animated in nevigation bar, not that much important.

@mercime I prefer not to use plugins as much as I could, besides in this case there is no hearty one (just some of not bad plugins in codecanion for purchasing and one on wordpress.org -menu effect- not working at all). So I’ll spend some hours to find the best way of sub menu animation specially for BP default theme and if I get a result I’ll send words.